FourierTransform.m

Complex Fourier Transform of a real time series. From zero to Nyquist frequency.

[rC,iC,Fn] = FOURIERTRANSFORM(X,dT) gives the components of the complex Fourier transform, complex(rC,iC), of the real time series X taken at the sampling interval dT (optional) via FFT.
Fn are the respective Fourier frequencies, from zero to Nyquist. This is one of the purposes of this simple program: only positive frequencies.

The other purpose is for the user to see how to get the same result via complex exponentials or Fourier trigonometric series (sines and cosines), although this methods are slower than the FFT.

The M-file comes with the example of the screenshot.

See also INVERSEFOURIERTRANSFORM.M:
http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=13328